Pneumatic jack



May 1, 1923. 1,454,010

. R. BERNAT PNEUMATIC JACK Filed Dec. 9. 1921 ill .19 l

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Fahd Banzai mm QM M tuted as follows:

Patented ay 1, 1923..

PNEUMATIC JACK;

Application filed December-9., 1921. Serial No. 521,216.

To all whom it may concern:

Be it known that I, R-AoUL BERNAT, citizen of the Republic of France residing at Bordeaux, France, 6v Rue des bouves, have invented a new Pneumatic Jack, of which the following is a specification.

This invention relates to a pneumatic jack having a piston packed by the action of an appropriate fluid under pressure and so arranged that the pressure of the compressed air sent into the apparatus acts both to produce the raising of the piston, fast with the head of the jack, and to'ensure, in a perfect and continuous manner, the tightness of the joint between the piston and the cylinder in which it moves. This pneumatic jack which is shown, by way of example, in sectional elevation in the annexed drawing is consti- It comprises a cylinder (1) provided with a bottom (2) and closed by, a cover (3). Within this cylinder a piston made in two parts 1', 4: is free to move, and between these parts is arranged a piece (5), whose straight section is that of a double T, and which is provided with an opening (6). This piece (5) serves to hold against the internal face of the parts 1' and 4" of the piston, two cup leathers 7 and 8, while leaving a free space between them designed to form thejoint between the cylinder and the piston. The two parts of this latter are screwed to the lower part of a tube (9) forming the lifting-bar of the jack and provided with openings (10) ensuring communication between the interior of the piston and the interior of the cylinder! (9). The upper part of this latter is so formed as to constitute the head (11) of the jack.

The cover (3) may be furnished with a packing (12) forming a guide for the lifting-bar of the jack, and with an air hole enabling the air to escape as fast as the piston rises in the cylinder (1 These two elements, however, are, not indispensable, the guiding ,of the lifting-bar of the jack having no need to be air-tight so permitting the escape of this latter during the progressive rise of the iston in the cylinder.

on the lhwer internal part of the tube (9) is furthermore screwed the base of a tube (14) open at its upper end.

Another tube (15), arranged within the tube (14), and whose upper open end is situated above that of this latter, as high up as possible in the inside of the tube (9),

is furthermore fitted to the bottom (2) of the cylinder (1) by means of a piece (16) screwed on to this bottom. This piece com prises an interior passage (17), (18), en'- a-bling the tube (15) to be placed into communication with a flexible tube (19), mounted, at (20,), on a nipple or socket of the said piece. This flexible tubepipe carries an obturating device or valve (21), similar to that of the inner tube of a pneumatic tyre, connected by its adjuta e (22) to'an air pump, an ordinary pump or pneumatic tyres or any reservoir of com'pressed'air, a Michelin flask for instance.

The direction of the working of this obturating device must be such that any return of air towards the pump or the .reservoir of compressed air is impossible.

The entire apparatus is mounted on a suitable support (23).

The free space on the interior of the piston, and .the annular space comprised be tween the two tubes (9) and (12%), are filled with a liquid, such as glycerine, oil, or water,

jor with a semi-fluid body, such as the sodoil of curriers; this liquid, or this semifluid body, rises to the upper part of the tube (9), and is capable of coming into contact with inner walls of the cylinder (1) by flowing through the space existing between the two cup leathers (7) and To introduce the aforesaid fluid or semifiuid body into the apparatus, it is poured through the air hole (13), (when there is one) and then this hole' is closed. The piston is then drawn towards the top of its cylinder by means of its lifting-bar (9), which has the effect of slightly driving cup leathers 7-. and 8, due to the movement of the piston, towards the interior of the hollow space of the piston, since'there is no pressure within the .piston to press the leathers 7 and 8 against the wall-of casing 1. The liquid accordingly passes between the leathers and wall of caslng 1 and into the interior of the piston, as well as into the space between the tubes 9 and 14.

In the case where the apparatus has no air hole, the fillin is effected by forcing the li uid, or semiuid tu e (15).

In these conditions of setting up, the apparatus will work in the following manner:

In the working of the rise, the air hole (13) is opened (when the apparatus is provided with one) then air under pressure 1s body, through the ing the path shown by other hand by descending between the tubes head of the jack.

and (15) on to the lower face of the piston on which it thus produces the rise, and hence that of thelifting-bar and of the The'pressure of the air on the liquid, or .semi-fluid-body, contained in the apparatus, has the effect of strongly pressing the cup leathers (7 and (8) against the inner walls of the cylinder (1), so ensuring in a perfect way, the tightness of the joint between the piston and the cylinder, and this in aconstant manner as the mass of the aforesaid body follows all the movements of the piston.

For working the fall, the controlling rod with which the obturating device (21) is furnished, is pressed down, the air is then driven out more or less quickly and the object raised by the jackdescends with a speed corresponding to that of the flow of the air. A certain pressure from the compressed air remains in the device as long as the piston is not at its lowest point, and leathers 7 and 8 are constantly forced against the cylinder 1 for making a tight packing.

,In all its various movements, the fluid contained in the piston and between tubes 9 and 14 is not displaced, and serves only to force the packin leathers 7 and 8 against the wall of cylin er 1 under the pressure of' compressed air' in the interior of' the device.

After the working, the air hole, (should there be one) is osed.

The above described arrangement may of course comprise various -1nodifications in its construction without departing from the spirit of the invention.

Having now particularly described the nature *of the said invention and in what manner the same is to beperformed, 1 declare that what ll claim is: I"

1. A pneumaticjack comprising a casing, a hollow piston in said casing, flexible gaskets positioned between the piston and casing, said hollow piston being formed to receive a fluid, means for supplying pressure fluid to the lower face of the piston, means for supplying fluidto the hollow piston, and means for permitting the pressure of the fluid supplied to the lower face of the piston,to be exerted in the hollow piston, whereby to pack the gaskets against the casing.

2. A pneumatic jack according to claim 1, said hollow piston carrying two spaced con centric tubes, the space between the concentric tubes being formed to receive a fluid and RAOUL BERNAT.

Witnesses:

PAUL W, Lnorom CHASSAINT. 

